The long term goal of this research is to determine the structure of a human transcriptional unit that encodes at least two functionally distinct transcripts, and determine how the gene products are related to normal development, homeostasis, and disease states or the susceptibility to disease. These studies may be relevant to certain forms of cardiovascular and pulmonary dysfunction, disorders of the hematopoietic system, responses to tumor-derived growth factors, and variability in responses to some drug treatment, development, aging and injury. It is the goal of the research proposed here to fill a void in our knowledge about the structure and expression of a human transcriptional unit that encodes: a set of calmodulin (CaM)-regulated protein kinases (nonmuscle/smooth muscle myosin light chain kinase (MLCK)), and a calcium binding protein that may be involved in the regulation of cell proliferation and differentiation. This knowledge is required for a full understanding of normal human development and the study of human diseases in future investigations. The specific aims for this funding period are: 1. elucidate the primary structure of human nonmuscle MLCK and MLCK-related gene products by using DNA sequence analysis of cloned DNA; 2. determine the structural organization and DNA sequence of the human transcriptional unit encoding these transcripts; and 3. initiate analyses of the expression of the protein products encoded by this transcriptional unit. Previous studies have shown that the transcriptional unit includes more than one gene and encodes multiple proteins whose production depends on the physiological state of the cell. One of the products is MLCK, a standard of comparison for CaM:protein kinase complexes. Therefore, knowledge gained from the study of this human protein kinase and its transcriptional unit have the potential of increasing our insight into how CaM:enzyme signal transduction complexes are regulated, and how perturbation of these complexes could result in pleiotropic effects. Knowledge about the structure, function, and regulation of expression of this novel transcriptional unit with multiple transcripts will provide a firm foundation for studies of in vivo growth factor-mediated events and the cell and molecular biology of stress responses.